Make Events V2 the default route and allow toggling legacy view via V2_EVENTS query parameter

[tareq89]

issue: #10707
country pr: opencrvs/opencrvs-countryconfig#1095
farajaland pr: opencrvs/opencrvs-farajaland#1768

Description

• Make Events V2 load from the root ('/') route by default.
• Allow switching to the legacy event view using the query parameter ?V2_EVENTS=false.
• Allow switching back to Events V2 using ?V2_EVENTS=true.
• Once Events V2 is fully released, it will become the default view, and the query parameter override will no longer be required.

Summary of Changes

• Updated routing configuration to default to Events V2.
• Retained query parameter mechanism for backward compatibility and testing.
• Removed environment-based toggling from country config.

Motivation

Simplifies configuration and ensures all environments start in V2 mode by default, while still supporting temporary toggling during migration or debugging.

Checklist

• I have linked the correct Github issue under "Development"
• I have tested the changes locally, and written appropriate tests
• I have tested beyond the happy path (e.g. edge cases, failure paths)
• I have updated the changelog with this change (if applicable)
• I have updated the GitHub issue status accordingly

[github-actions]

Oops! Looks like you forgot to update the changelog. When updating CHANGELOG.md, please consider the following:

• Changelog is read by country implementors who might not always be familiar with all technical details of OpenCRVS. Keep language high-level, user friendly and avoid technical references to internals.
• Answer "What's new?", "Why was the change made?" and "Why should I care?" for each change.
• If it's a breaking change, include a migration guide answering "What do I need to do to upgrade?".

[ocrvs-bot]

Your environment is deployed to https://ocrvs-10707.e2e-k8s.opencrvs.dev